This invention relates to a burner for combusting air and fuel characterized in that the fuel is thoroughly mixed on a local basis with modified combustion air in a manner so that resultant combustion is complete and oxides of nitrogen (NO.sub.x) in the exhaust gas are substantially reduced. "Fuel" as used herein means gas and/or liquid fuel.
Fuel is burned by mixing air with it, oxygen from the air being combined with carbon and hydrogen present in the fuel with the release of substantial heat. If fuel is thoroughly mixed with air and combustion is carried out under ideal conditions the results of the combustion are primarily carbon dioxide and water in vapor form. These components are commonly found in the atmosphere and are essentially free of hazard to the environment. However, when fuel is burned at a high temperature, excess air environment, a portion of the nitrogen, which makes up a major component of the atmosphere, will react with oxygen in the atmosphere to produce oxides of nitrogen (NO.sub.x). It is well known that, other conditions being equal, NO.sub.x production increases as the temperature of the combustion process increases. Oxides of nitrogen gases are considered to be an environmental hazard.
The present invention is an improved burner for combusting fuel, whether a gas or a liquid or a combination of both, with modified air in a manner to result in less NO.sub.x than is available by the present generation of burners. The present generations of burners are commonly referred to as "Low NO.sub.x Burners" or "Low NOx Burners".
For background information relating to burners configured to reduce NO.sub.x production, reference may be had to the following U.S. Pat. Nos. 4,505,666; 4,483,832; 4,162,140; 5,284,438; 5,180,300; 4,004,875; 5,073,105 and 2,918,117 which are incorporated herein by reference.